[Cardiac contractility modulation]

Heart failure (HF) will be one of the biggest medical challenges in the coming years, with increasing prevalence in an aging society. It is associated with a poor prognosis and impaired quality of life-despite steadily improving medical therapy which has resulted in a steady decrease in mortality and an increase in quality of life. In medically refractory patients with impaired left ventricular (LV) function, left bundle branch block and wide QRS complex (≥130 ms) cardiac resynchronization therapy (CRT) in addition to medical therapy has become the gold standard. Additionally, other therapeutic modalities such as vagal stimulation are being clinically tested but as yet have no general therapeutic recommendation. Overall, CRT patients represent only one-third of all HF patients and about 25% are "non-responders" who do not benefit from CRT.In HF patients with an LVEF between 25 and 45% and a QRS duration <130 ms who are not suitable for CRT, cardiac contractility modulation (CCM) is currently a therapeutic option that has been shown in several randomized trials to be efficacious and safe. It reduces the frequency of HF hospitalizations and improves HF symptoms, functional capacity, and quality of life. The goal of this article is to present mechanisms of action, major clinical studies, current indications, and recent developments of CCM for the treatment of patients with chronic HF.